first time multithreading an app

Question

ive never multithreaded an app before. i have a bot class. this bot is supposed to navigate its way through a corridor. the corridor is drawn onto a forum. all the bots are created on the forum, given various parameters, added to an arraylist, and their processing methods are called through a loop. im trying to time the duration of processing for each bot, but the last bot always has the accumulated time for all bots. if i multithread i imagine i could get rid of this. can anyone explain how i might go about this?